Method for transporting a curved wind turbine blade and associated transportation device

ABSTRACT

A method of transporting a wind turbine blade with a curved central longitudinal axis includes loading the wind turbine blade onto a transportation device including first and second support bearings. The wind turbine blade is loaded in a first orientation in which the curved central longitudinal axis is located in a generally vertical plane. When the transportation device is preparing to turn, the wind turbine blade is rotated to a second orientation before or during turning such that the curved central longitudinal axis is located in a generally horizontal plane and bends around the turn. As a result, the curved wind turbine blade and transportation device can traverse tighter curves and turns during travel to an assembly site or quayside.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of pending U.S. patentapplication Ser. No. 14/369,933 filed Jun. 30, 2014 which is a U.S.National Phase Application of PCT/DK2012/050485 filed Dec. 20, 2012,which claims the benefit of U.S. Provisional Application Ser. No.61/581,342 filed Dec. 29, 2011. International applicationPCT/DK2012/050485 designates the United States and claims priority toDanish Patent Application No. PA 2011 70770 filed Dec. 30, 2011. Each ofthese applications is incorporated by reference herein in its entirety.

TECHNICAL FIELD

This application relates generally to wind turbines, and moreparticularly to a transportation device and method for transporting awind turbine blade in which the wind turbine blade may be rotated whenmounted on the transportation device.

BACKGROUND

In a typical on-shore wind turbine installation, various components ofthe wind turbine, such as, for example, the nacelle, tower or towersections, rotor hub, rotor blades, etc., may be transported to theinstallation site separately and then assembled together on site so asto result in an operational wind turbine. In this regard, due to therelatively large size of some of these components, the transportationthereof is typically carried out using one or more tractor trailers,which travel along the existing network of roads, highways, expressways,etc. (collectively referred to herein as roads) to the installationsite. Additionally, in off-shore wind turbine installations, which canbe significantly larger than on-shore installations, wind turbinecomponents are typically transported using tractor trailers on theexisting network of roads from a factory, for example, to quayside wherethe components may be loaded onto boats for transport to the off-shoreinstallation site.

Many of the existing roads used in the transportation of wind turbinecomponents are divided into lanes so as to accommodate other vehiclesmoving in, for example, the same direction or an opposing direction, andmay further have a shoulder on the sides of the outer most lanes. Theselanes have a certain width that, in the normal course, accommodates mostof the traffic on the road. Moreover, in many countries, regions, etc.,various road signage is located just off the shoulders for aiding,informing, guiding, etc. those traveling on the road. In many instances,the distance between the inner boundary of the outer lane and the roadsignage may be between 5 to 6 meters. This distance then represents themaximum width of a vehicle (or a load carried by the vehicle) that maytravel on the road without obstructing vehicles traveling in an adjacentlane and without damaging or otherwise destroying the road signageadjacent the road.

Additionally, many existing roads pass under bridges at highwayintersections and similar junctions. In some circumstances, thesebridges only provide a height clearance of 4 to 5 meters from thesurface of the road. This height clearance represents the maximum heightof a vehicle and its associated load that may travel on the road withoutimpacting the bridge. Most existing roads do not extend in a completelystraight path, and the transport path from the factory to theinstallation site or quayside may include a number of curves and turnsat road intersections. Therefore, a vehicle transporting a wind turbinecomponent must also traverse curved paths in the road as well asrelatively sharp corners at road intersections, in addition to stayingwithin the maximum width during normal operation and staying within themaximum height when going under a bridge.

Wind turbine blades are typically transported to an installation site orquayside on a tractor trailer. Conventionally, the blade was typicallyloaded on a tractor trailer and secured thereto in a fixed position sothat the blade did not essentially move during transit. However, thetrend in wind turbine construction has been for the power output andphysical size of the wind turbine to scale upward. As a result, morerecent wind turbine blades have included larger lengths and widths thatincrease the difficulties of transporting the blades on existing roads.Transportation devices have been developed for transporting these largerwind turbine blades.

For example, the transportation device described in U.S. Pat. No.7,303,365 to Wobben operates to rotate the wind turbine blade along itsstraight longitudinal axis during transport so that a maximum width ofthe blade is oriented generally horizontal to fit under bridges andoriented generally vertical to limit the total width of the vehicle andload during normal operation. However, this transportation devicecontinues to struggle with managing the length of the blade during sharpturning or cornering operations.

Also US 2011/0142589 discloses a way of dealing with passing lowpassages, however in relation to transporting curved blades. A curvedblade is held in a pivotable and slidable cradle (FIG. 2, reference140). While passing low passages the curved blade is tilted to pass afirst section of the passage by keeping a root end (56) of the bladelow, while the tip end (54) is high, and passing the remaining part ofthe passage by elevating the root end (56) of the blade, which lowersthe tip end (54) of the blade (FIG. 3). Again, this document only relateto passing low passages and not turning in any way.

DEFINITIONS

Normally in the past wind turbines blades were generally straight,whereby is has become normal terminology to use the term “a longitudinalaxis” of a blade. In order not to confuse the skilled reader, it hasbeen chosen in this present document to stick with the term“longitudinal axis”, although the blades in the present context, seebelow, are curved i.e. e.g. being prebent in a way, such that when theblades are mounted on a wind turbine facing the wind, the curvaturegradually form the blade to lean into the wind, i.e. being prebent in anupwind direction. This in the following described as the blades have a“curved longitudinal axis” or “central curved longitudinal axis”. Alsowith respect to normal terminology, when looking at a normal blade, i.e.in a non-prebent blade a “flapwise plane” would exist. This term isagain chosen to stick with, in order not to confuse a skilled reader. Sowhen the terms “flapwise plane”, “horizontal plane” or “vertical plane”are used in the present context, this is to be read and understood as a“flapwise direction”, “horizontal direction” or “vertical direction”; orunderstood as a “a number of flapwise directions”, “a number ofhorizontal directions” or “a number of vertical directions”. Moreover,the formulation that “the curved longitudinal axis is located in agenerally vertical plane” is to be understood as a curved blade havingits curvature of the longitudinal axis, e.g. when seen as a drawn line,this curved axis is actually and substantially lying within a verticalplane. Similarly, the formulation that “the curved longitudinal axis islocated in a generally horizontal plane” is to be understood as a curvedblade having its curvature of the longitudinal axis, e.g. when seen as adrawn line, this curved axis is actually and substantially lying withina horizontal plane. These definitions follow clearly and unambiguouslyfrom the appended Figs and description of the figures as well as thedocument as a whole.

A new trend in wind turbine construction is forming curved wind turbineblades, as addressed above, having a substantially curved longitudinalaxis in at least one plane (for example, in the flapwise plane). Thesecurved wind turbine blades, or prebent blades are believed to produceenhanced efficiency of power generation with lower bending and torsionalstresses on the blade. But curving the wind turbine blade may increase amaximum effective blade width in the plane of curvature, which would bemeasured in the example above (flapwise plane) between a leeward side atthe center of the blade and a windward side at the tip or root of theblade. With the ever-expanding physical size of wind turbine blades, itis expected that these maximum effective blade widths in the plane ofcurvature will continue to increase, which will make the transportationthereof to the installation site or quayside on existing roads moreproblematic. For example, the dimensions may make it such that the windturbine blade may not be transported on a tractor trailer using existingroads without a significant risk of interfering with adjacent traffic,damaging road signage, or cutting corners at an intersection. In thisregard, the conventional transportation devices described above areineffective at handling curved wind turbine blades in these varying roadconditions.

Thus, there is a need for a transportation method and associated devicethat allows large-scale curved wind turbine blades to be transported towind turbine installation sites or quayside via the existing network ofroads.

SUMMARY

To address these and other shortcomings, a method of transporting acurved wind turbine blade includes loading the wind turbine blade onto atransportation device including first and second support bearingsconfigured to receive the wind turbine blade. The wind turbine blade isloaded in a first orientation such that a curved central longitudinalaxis of the blade is located in a generally vertical plane. When thetransportation device is preparing to turn in a turning direction, themethod also includes rotating the wind turbine blade to a secondorientation before or during turning. In the second orientation, thecurved central longitudinal axis of the blade is located in a generallyhorizontal plane and bends in the turning direction. As a result, thecurved wind turbine blade and transportation device can traverse tightercurves and turns during travel to an assembly site or quayside.

In one aspect, rotating the wind turbine blade to the second orientationincludes rotating the wind turbine blade along the central longitudinalaxis and translating at least one of the first and second supportbearings in a direction transverse to the central longitudinal axis. Oneof the first and second support bearings may also rotate about an axisperpendicular to the central longitudinal axis during rotation of thewind turbine blade to the second orientation. More particularly, thecurved central longitudinal axis is curved about a center of curvature,and this center of curvature is moved beyond one of the sides of thetransportation device when the wind turbine blade is moved to the secondorientation. In the first orientation, this center of curvature islocated in a vertical plane proximate to a longitudinal centerline ofthe transportation device. Accordingly, the transport device alsoincludes a counterweight that moves towards the same side of thetransportation device as the center of curvature to balance out tippingmoments caused by the curved wind turbine blade in the secondorientation. After the transportation device has turned, the windturbine blade may be rotated back to the first orientation.

In another aspect, the transportation device includes a drive mechanismfor rotating the wind turbine blade between the first and secondorientations. In this regard, the method further includes determiningwith a controller that the transportation device is preparing to drivearound a curve and actuating the drive mechanism with the controller torotate the wind turbine blade before or during that curve. For example,the controller may include a user interface receiving commands from adriver of the truck to rotate the wind turbine blade when the driverindicates that the transportation device is approaching a curve or aturn.

In another example, the controller receives input signals from a turningsensor on a steering wheel of the transportation device, and thecontroller actuates rotation of the wind turbine blade when the turningsensor detects rotation of the steering wheel beyond a predeterminedthreshold. Alternatively, the controller receives input signals from aglobal positioning system when that system determines that thetransportation device is approaching a curve or a turn. In this regard,the control of the rotation of the wind turbine blade may be manual orautomatic.

In one embodiment of the invention, the transportation device includes aunitary tractor having each of the first and second support bearings. Inthis embodiment, rotating the wind turbine blade to the secondorientation includes rotating the wind turbine blade along the centrallongitudinal axis. Additionally, the first support bearing is translatedin a vertical direction relative to a fixed position of the secondsupport bearing, and the first support bearing is also rotated about ahorizontal axis transverse to the central longitudinal axis and rotatedabout a vertical axis.

In another embodiment, the transportation device includes a tractor withthe first support bearing and a first trailer including the secondsupport bearing. The first trailer is connected to the tractor by thewind turbine blade. In this embodiment, rotating the wind turbine bladeto the second orientation includes rotating the wind turbine blade alongthe central longitudinal axis.

Additionally, at least one of the first and second support bearings aretranslated in a vertical direction, and the first and second supportbearings are also rotated about corresponding horizontal axes transverseto the central longitudinal axis.

The transportation device may further include a second trailer carryinga third support bearing located between the first and second supportbearings. When the wind turbine blade is rotated to the secondorientation, the third support bearing is optionally translated in avertical direction opposite the translating movement of the first andsecond support bearings. The third support bearing and the secondtrailer also move along a horizontal axis transverse to the centrallongitudinal axis so that the third support bearing follows movements ofthe central portion of the wind turbine blade.

In another embodiment of the invention, a transportation device fortransporting a curved wind turbine blade includes a tractor, a firstsupport bearing coupled to the tractor, and a second support bearing.The first and second support bearings receive the wind turbine blade.The transportation device also includes a drive mechanism operable torotate the wind turbine blade within the first and second supportbearings between a first orientation and a second orientation. A curvedcentral longitudinal axis of the wind turbine blade is located in agenerally vertical plane in the first orientation and is located in agenerally horizontal plane in the second orientation.

Advantageously, when the tractor is preparing to turn in a turningdirection, the drive mechanism rotates the wind turbine blade to thesecond orientation before or during turning such that the curved centrallongitudinal axis bends in the turning direction.

In one aspect, the transportation device includes a bearing drive devicecoupled to one of the first and second support bearings. The bearingdrive device translates the support bearing in a vertical directionduring rotation of the wind turbine blade between the first and secondorientations. In another aspect, each of the first and second supportbearings includes a frame, a support located within the frame, and anannular bearing positioned between the frame and the support. Thesupport includes an aperture sized to closely receive the wind turbineblade. The annular bearing enables free rotation of the support and thewind turbine blade along the central longitudinal axis. The drivemechanism may be independent from the first and second support bearingsor may be operatively associated with at least one of the first andsecond support bearings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate various embodiments of theinvention and, together with a general description of the inventiongiven above and the detailed description of the embodiments given below,serve to explain the embodiments of the invention.

FIG. 1 is a diagrammatic view of a wind turbine having curved blades;

FIG. 2A is a top view of the transportation device of the currentinvention approaching and entering a turn with a wind turbine blade toillustrate potential hazards of navigating the turn;

FIG. 2B is a schematic view of the transportation device of the currentinvention, illustrating various control and driven components;

FIG. 3 is a perspective view of the support bearing used with thetransportation device of FIGS. 2A and 2B;

FIG. 4A is a side view of a first embodiment of the transportationdevice of the current invention, showing the wind turbine blade in thefirst orientation;

FIG. 4B is a top view of the transportation device and wind turbineblade of FIG. 4A in the first orientation;

FIG. 4C is a top view of the transportation device and wind turbineblade of FIG. 4A during travel along a straight road;

FIG. 5A is a side view of the transportation device of FIG. 4A, showingthe wind turbine blade rotated to a second orientation;

FIG. 5B is a top view of the transportation device and wind turbineblade of FIG. 5A in the second orientation;

FIG. 5C is a top view of the transportation device and wind turbineblade of FIG. 5A during travel around a curve or turn;

FIG. 6A is a rear view of the transportation device and wind turbineblade of FIG. 4A in the first orientation;

FIG. 6B is a rear view of the transportation device and wind turbineblade of FIG. 5A in the second orientation;

FIG. 7A is a side view of a second embodiment of the transportationdevice of the current invention, showing the wind turbine blade in thefirst orientation;

FIG. 7B is a top view of the transportation device and wind turbineblade of FIG. 7A in the first orientation;

FIG. 7C is a top view of the transportation device and wind turbineblade of FIG. 7A during travel along a straight road;

FIG. 8A is a side view of the transportation device of FIG. 7A, showingthe wind turbine blade rotated to a second orientation;

FIG. 8B is a top view of the transportation device and wind turbineblade of FIG. 8A in the second orientation; and

FIG. 8C is a top view of the transportation device and wind turbineblade of FIG. 8A during travel around a curve or turn.

DETAILED DESCRIPTION

With reference to FIG. 1 and in accordance with an embodiment of theinvention, a wind turbine 10 includes a tower 12, a nacelle 14 disposedat the apex of the tower 12, and a rotor 16 operatively coupled to agenerator (not shown) housed inside the nacelle 14. In addition to thegenerator, the nacelle 14 houses miscellaneous components required forconverting wind energy into electrical energy and various componentsneeded to operate, control, and optimize the performance of the windturbine 10. The tower 12 supports the load presented by the nacelle 14,the rotor 16, and other components of the wind turbine 10 that arehoused inside the nacelle 14, and also operates to elevate the nacelle14 and rotor 16 to a height above ground level or sea level, as may bethe case, at which faster moving air currents of lower turbulence aretypically found.

The rotor 16 of the wind turbine 10, which is represented as ahorizontal-axis wind turbine, serves as the prime mover for theelectromechanical system. Wind exceeding a minimum level will activatethe rotor 16 and cause rotation in a direction substantiallyperpendicular to the wind direction. To this end, the rotor 16 of windturbine 10 includes a central hub 18 and at least one blade 20 thatprojects outwardly from the central hub 18. In the representativeembodiment, the rotor 16 includes three blades 20 at locationscircumferentially distributed thereabout, but the number may vary. Theblades 20 are configured to interact with the passing air flow toproduce lift that causes the central hub 18 to spin about a longitudinalaxis 22.

The design and construction of the blades 20 are familiar to a personhaving ordinary skill in the art, although the blades 20 illustrated arecurved wind turbine blades 20 used to improve the efficiency and reducethe stress loading of the blade 20 during operation. More particularly,each of the curved wind turbine blades 20 includes a curved centrallongitudinal axis 24 extending from a root end 26 adjacent the centralhub 18 to a tip end 28 as schematically shown by phantom lines inFIG. 1. In this regard, each wind turbine blade 20 has a non-linearlongitudinal profile that increases the effective flapwise width of theblade, as described in further detail below. It will be understood thatthe curved central longitudinal axis may be curved in differentdirections, such as forward or aft sweep, or coning, which will be of asubstantially smaller extent, than the curvature shown in these figureswithout departing from the scope of the invention.

The wind turbine 10 may be included among a collection of similar windturbines belonging to a wind farm or wind park that serves as a powergenerating plant connected by transmission lines with a power grid, suchas a three-phase alternating current (AC) power grid. The power gridgenerally consists of a network of power stations, transmissioncircuits, and substations coupled by a network of transmission linesthat transmit the power to loads in the form of end users and othercustomers of electrical utilities. Under normal circumstances, theelectrical power is supplied from the generator to the power grid asknown to a person having ordinary skill in the art.

As discussed above, the wind turbine 10 is typically assembled onsite atthe wind farm or the wind park. Consequently, the components of the windturbine 10 including the curved wind turbine blades 20 must betransported from a factory to the installation site via travel along theexisting network of roads. As well understood, transportation devicessuch as tractor trailers are used to transport the wind turbine blades20 along the roads. FIG. 2A illustrates one such transportation device30 including a tractor 32 with first and second support bearings 34, 36holding the curved wind turbine blade 20. As is common when travelingalong the existing network of roads, the tractor 32 is approaching acurve or a turn that must be navigated while keeping the wind turbineblade 20 within the boundaries of the road. However, if the wind turbineblade 20 is kept in the orientation shown in FIG. 2A, it may bedifficult, if not impossible, for the tractor 32 to navigate the turnwithout either swinging the tip end 28 of the blade 20 beyond theboundary of the road, which could cause damage to signs or otherstructures located just beyond the boundary, or cutting across the inneredge of the corner with the tractor 32 and the blade 20. Each of thesepossible problems is illustrated by the phantom-line representations ofthe transportation device 30 after entering the turn shown in FIG. 2A.

As described in further detail below, the transportation device 30 ofthe current invention advantageously includes the support bearings and adrive mechanism that actuate rotation of the curved wind turbine blade20 from a generally vertical first orientation when the transportationdevice 30 is about to turn around a curve in the road or at a roadintersection, or alternatively, during turning, to a generallyhorizontal second orientation. Accordingly, the curved centrallongitudinal axis 24 of the blade 20 bends to follow the curvature ofthe turn or the road, thereby reducing or minimizing obstruction ofother lanes or cutting across corners with the wind turbine blade 20(examples are shown in FIGS. 5C and 8C and are described in furtherdetail below). In this regard, the transportation device 30 of thecurrent invention provides improved positioning of the wind turbineblade 20 relative to the boundaries of the road as shown in thephantom-line examples of FIG. 2A. To this end, the transportation device30 and method of the current invention enables improved transportationof larger curved wind turbine blades 20 along the existing network ofroads as compared to conventional transportation devices.

With reference to FIGS. 2A and 2B, the transportation device 30 of thecurrent invention is shown. The transportation device 30 includes thetruck or tractor trailer hereinafter referred to as a tractor 32 and atleast two support bearings 34, 36 (only the first support bearing 34shown in FIG. 2B) for holding the curved wind turbine blade 20. Thetransportation device 30 and the tractor 32 include a longitudinalcenterline LC that runs longitudinally to divide the transportationdevice 30 into equal halves extending transversely away from thelongitudinal centerline LC. More particularly, the tractor 32 includesfirst and second longitudinal sides 35, 37 on opposite transverse sidesof the longitudinal centerline LC. The transportation device 30 alsoincludes a drive mechanism 38 for rotating the wind turbine blade 20 andat least one bearing drive device 40 for moving the correspondingsupport bearing 34 to accommodate the rotation of the wind turbine blade20. The drive mechanism 38 and the bearing drive device 40 areoperatively coupled to a controller 42 that actuates rotational movementof the wind turbine blade 20 when required by the transportation device30 encountering a turn or a curve in the road. The controller 42 may beconfigured to automatically actuate the rotation or respond to a manualinput signal to rotate the wind turbine blade 20 as described in furtherdetail below. As explained in further detail below, it will beunderstood that the drive mechanism 38 may directly engage the windturbine blade 20 to actuate rotation of the wind turbine blade 20 or mayuse the bearing drive device 40 and/or other drive devices associatedwith the support bearing 34, 36 to rotate the wind turbine blade 20 invarious embodiments within the scope of the invention. To this end, thedrive mechanism 38 may be independent from the support bearings 34, 36or may be directly associated with the support bearings 34, 36 such asby integration with the bearing drive device 40.

In this regard, the transportation device 30 also includes a sensingdevice 44 configured to determine when the tractor 32 is turning orabout to turn around a curve or at an intersection. Several examples ofthe sensing device 44 are shown schematically in FIG. 2B. In one aspect,the sensing device 44 includes a user interface 46 located within thecab 48 of the tractor 32. The user interface 46 receives manual or voicecommands from a driver of the tractor 32 when the driver indicates thatthe tractor 32 is approaching a turn or a curve. When such a command isreceived, the user interface 46 sends a signal to the controller 42 toactuate rotation of the wind turbine blade 20 so that the curved centrallongitudinal axis 24 bends around the turn rather than cutting acrossthe turn (as explained below). Accordingly, the user interface 46enables manual control of the rotation of the wind turbine blade 20.

Alternatively, the sensing device 44 includes a turning sensor 50 inanother aspect. The turning sensor 50 is coupled to the steering wheel(not shown) in the cab 48 of the tractor 32 and determines whether thesteering wheel has been rotated beyond a predetermined threshold. Whenthe turning sensor 50 detects a turn sharp enough to overcome thepredetermined threshold, the turning sensor 50 sends a signal to thecontroller 42 to automatically rotate the wind turbine blade 20 tofollow the curvature of the turn being performed. The predeterminedthreshold may be programmed to be any value based on the length andcurvature of the wind turbine blade 20 being transported. In anotheraspect, the sensing device 44 includes a global positioning system (GPS)52 that detects when the tractor 32 is approaching a curve in the roador a turn at an intersection. As well understood, the GPS 52communicates with a satellite interface 54 to detect the currentlocation and movements of the tractor 32 to determine when such a curveor turn is going to occur. Similar to the turning sensor 50, the GPS 52sends a signal to the controller 42 to automatically cause rotation ofthe wind turbine blade 20 immediately before or during the turn. It willbe appreciated that these and other types of sensing devices 44 may beused, alone or in combination with the sensing devices 44 describedabove, to signal the controller 42 to actuate rotation of the windturbine blade 20 either manually or automatically in other embodimentswithout departing from the scope of the invention.

When rotating a curved wind turbine blade 20, a substantial portion ofthe mass of the wind turbine blade 20 may move off-center from thelongitudinal center line LC of the transportation device 30. In order tocounter any force-moments that may tend to cause the transportationdevice 30 to tip over, in one embodiment a counterweight 56 may also beprovided on the tractor 32. The counterweight 56 is operably connectedto the controller 42 as shown in FIG. 2B such that whenever thecontroller 42 actuates rotation of the wind turbine blade 20, acorresponding movement of the counterweight 56 is also actuated. Moreparticularly, the counterweight 56 shifts towards one side 35 of thetransportation device 30 while the central portion of the wind turbineblade 20 shifts towards an opposite side 37 as described in furtherdetail with reference to FIG. 4B below. The counterweight 56 thereforeapplies an opposing force-moment on the transportation device 30 thatreduces the possibility of a tip over during a turning operation.

With reference to FIG. 3, an exemplary embodiment of the support bearing34 (or 36) used with the transportation device 30 is shown. For thepurposes of description, directions are defined in FIG. 3 as the Z-axiscorresponding to the horizontal axis along the longitudinal extent ofthe tractor 32 and generally the wind turbine blade 20, the Y-axiscorresponding to the vertical axis, and the X-axis corresponding to thehorizontal axis transverse to the longitudinal direction. The supportbearing 34 includes a frame 60 pivotally coupled to a pair of supportarms 62 that extend generally vertically (along the Y-axis shown in FIG.3) from a platform base 64. The pivotal coupling of the frame 60 enablesthe frame 60 to freely rotate about the X-axis as shown in FIG. 3. Theplatform base 64 is rotatably mounted on the tractor 32 or a trailer asdescribed in operation in further detail below. More specifically, theplatform base 64 may be mounted on a rotational bearing (not shown) tothe tractor 32 or a trailer so that the entire support bearing 34 isrotatable about the vertical Y-axis. Each of the support arms 62includes a bearing drive device (schematically shown as 40 in FIG. 2B)such as the hydraulic linear actuators 66 shown in FIG. 3. Thesehydraulic linear actuators 66 operate to translate or move the frame 60upwardly or downwardly along the Y-axis. Thus, the frame 60 is rotatablearound the vertical Y-axis and is moveable along the vertical Y-axis.

Additionally, the support bearing 34 also enables freedom to rotatealong the longitudinal or Z-axis. To this end, the support bearing 34includes a support 68 (e.g., a foam support) positioned within the frame60 and an annular bearing 70 located between the frame 60 and thesupport 68. In one example, the support 68 is an injection moldedsupport structure having a generally cylindrical shape and including anaperture 72 extending through the support 68. The aperture 72 is sizedto closely receive a particular portion of the wind turbine blade 20 tothereby cushion and support the wind turbine blade 20, as shown infurther detail with reference to the particular embodiments shown inFIGS. 4A-8C. The support 68 will therefore typically be designed for aparticular type of curved wind turbine blade 20 and could be replacedwith a different support 68 when a differently sized or shaped blade 20is to be transported. The annular bearing 70 is any conventional type ofbearing (e.g., roller bearing) enabling free rotation of the support 68with respect to the frame 60 about the longitudinal Z-axis. In sum, theparticular portion of the wind turbine blade 20 that is held within theaperture 72 of the support 68 is capable of rotation about all axes (X,Y, and Z) and is also moveable by translation along at least one of theaxes. It will be understood that the support bearing 34 and/or the drivemechanism 38 may include locking mechanisms (not shown) for preventingundesirable rotations or movements of the wind turbine blade 20 duringtransport. Consequently, the support bearing 34 reliably supports thewind turbine blade 20 in multiple orientations as the wind turbine blade20 rotates generally along its longitudinal axis 24.

The operation of the transportation device 30 according to a firstembodiment is shown in FIGS. 4A-6B. In this embodiment, thetransportation device 30 a and all previously described components areshown with the same reference numbers where appropriate, with theaddition of an “a” on the end of the reference number to indicate thisparticular embodiment. The transportation device 30 a of this embodimentincludes a tractor 32 a and first and second trailers 80, 82 coupled tothe tractor 32 a by the wind turbine blade 20. It will be understoodthat additional connections such as cable connections (not shown) may beprovided between the tractor 32 a and the trailers 80, 82 in someembodiments consistent with the invention. The tractor 32 a includes afirst support bearing 34 a as previously described, which receives thewind turbine blade 20 therethrough proximate the root end 26 of the windturbine blade 20. The first trailer 80 includes a second support bearing36 a as previously described, which receives the wind turbine blade 20therethrough proximate the tip end 28 of the wind turbine blade 20. Thesecond trailer 82 is located between the tractor 32 a and the firsttrailer 80 and includes a third support bearing 84 similar to the firstand second support bearings 34 a, 36 a. The third support bearing 84receives the wind turbine blade 20 therethrough adjacent a centralportion of the wind turbine blade 20. In this regard, the wind turbineblade 20 is fully supported at three locations along its longitudinallength. It will be understood that the second trailer 82 and the thirdsupport bearing 84 may be omitted in further non-illustrated embodimentsof the invention depending on, for example, the length of the windturbine blade 20 and possibly other factors. In this regard, the secondtrailer 82 and the third support bearing 84 are optional features thatmay be removed in other embodiments consistent with the scope of theinvention. Additionally, the first trailer 80 and the second supportbearing 36 a could alternatively be positioned to receive the centralportion of the wind turbine blade 20 rather than proximate the tip end28 in other embodiments consistent with the current invention.

Returning to FIGS. 4A-4C, the wind turbine blade 20 is loaded onto thetransportation device 30 a in a first orientation in which the curvedcentral longitudinal axis 24 of the blade 20 is located in a generallyvertical plane substantially located (or only slightly offset from)adjacent a longitudinal centerline LC of the tractor 32 a. As shown inthe side view of FIG. 4A, the curvature of the central longitudinal axis24 also generally defines a center of curvature CC located within thatvertical plane roughly centered on the tractor 32 a. The curvature ofthe central longitudinal axis 24 in this embodiment is along theflapwise direction (i.e., between the pressure side and the suction sideof the blade 20) so that the wind turbine blade 20 defines an effectiveflapwise width FW shown in FIG. 4A. This effective flapwise width FW islarger than the maximum edgewise width EW shown in FIG. 4B and measuredbetween the leading and trailing edges of the wind turbine blade 20.Accordingly, the wind turbine blade 20 is loaded and normally kept inthis first orientation so that the transportation device 30 a and thewind turbine blade 20 in combination fit within the boundaries of a lane86 on a road 88 as shown in FIG. 4C.

As shown in the first orientation of FIGS. 4A and 4B, the first andsecond support bearings 34 a, 36 a are pivoted in the X-axis slightlytowards each other so that the corresponding supports 68 a follow theprofile of the wind turbine blade 20 near the root end 26 and the tipend 28. Also in this first orientation, the bearing drive devices 66 aof each of the first and second support bearings 34 a, 36 a extend thecorresponding support arms 62 a higher than the support arms 62 a of thethird support bearing 84 at the center portion of the wind turbine blade20. The counterweight 56 a is also centrally located on the tractor 32 abecause the mass of the wind turbine blade 20 is not locatedsubstantially off-center from the longitudinal centerline LC.Accordingly, each of the support bearings 34 a, 36 a, 84 reliablysupports the corresponding section of the wind turbine blade 20 duringnormal transport with the transportation device 30 a.

When the transportation device 30 a approaches a turn or curve in theroad 88 (as sensed/determined by one or more of the various sensingdevices 44 described above), the controller 42 actuates rotation of thewind turbine blade 20 generally about the central longitudinal axis 24to a second orientation with the drive mechanism 38 a, or alternatively,with the bearing drive device 66 a, as shown in FIGS. 5A-5C. In oneexample, the drive mechanism 38 a may directly couple to the windturbine blade 20 such as at the root end 26 for directly rotating theblade 20 as previously performed in the art (e.g., the rotationmechanism described in U.S. Pat. No. 7,303,365 to Wobben). Alternativelyor in addition, the drive mechanism 38 a includes a mechanically orhydraulically powered device that rotates the supports 68 a of one ormore of the corresponding support bearings 34 a, 36 a, 84 to causerotation of the wind turbine blade 20. It will be understood that othertypes of drive mechanisms 38 a known in the art for turning wind turbineblades 20 may also be used within the scope of this invention.

In addition to the rotation of the wind turbine blade 20 along thecentral longitudinal axis 24, the controller 42 may also actuateadditional movements of the support bearings 34 a, 36 a and thecounterweight 56 a. More particularly, the bearing drive devices 66 a ofthe first and second support bearings 34 a, 36 a translate thecorresponding support arms 62 a downwardly along the Y-axis while thebearing drive device 66 a of the third support bearing 84 translates thecorresponding support arms 62 a upwardly in the Y-axis. Thesetranslational movements are shown by arrows 90 in FIG. 5A.Alternatively, the first and second support bearings 34 a, 36 a maytranslate downwardly along the Y-axis while the third support bearing 84remains stationary. Additionally, the first and second support bearings34 a, 36 a freely rotate about both the transverse X-axis (as shown byarrows 92 in FIG. 5A) and the vertical Y-axis (as shown by arrows 94 inFIG. 5B) away from one another to accommodate the rotation of the windturbine blade 20. The third support bearing 84 and the second trailer 82also translate along the transverse X-axis to follow the movement of thecentral portion of the wind turbine blade 20 as indicated by arrow 96 inFIG. 5B. The collective effect of each of these rotational andtranslational movements is that the wind turbine blade 20 rotates to thesecond orientation in which the curved central longitudinal axis 24 isdisposed in a generally horizontal plane as shown. To this end, thecurved central longitudinal axis 24 is moved to bend around the turn tobe performed. It will be understood that in alternative embodiments suchas the one described above with an omitted second trailer 82 and a firsttrailer 80 at the center portion of the wind turbine blade 20, only oneof the first and second support bearings 34 a, 36 a would be required totranslate along the Y-axis during rotation of the wind turbine blade 20.

At the same time as these rotational and translational movements of thethree support bearings 34 a, 36 a, 84, the controller 42 may move thecounterweight 56 a with respect to the longitudinal centerline LC to theopposite side (35 a) of the tractor 32 a as the central portion of thewind turbine blade 20 to equalize force-moments applied to the tractor32 a. In other words, the counterweight 56 a moves to the same side 35 aof the tractor 32 a as the center of curvature CC of the centrallongitudinal axis 24 of the blade 20. The likelihood of thetransportation device 30 a tipping over while traversing the turn isreduced by this movement of the counterweight 56 a.

The benefits of rotating the wind turbine blade 20 to the secondorientation are most clearly shown in FIG. 5C, which illustrates thetransportation device 30 a of this embodiment during the turn around thecurve in the road 88. In contrast to the turn illustrated on the innerside of the road in FIG. 2A, the movements of the wind turbine blade 20and the transportation device 30 a to the second orientation enable thewind turbine blade 20 to bend around the curve rather than cut across aboundary 98 of the road 88. More specifically, the curve generallydefines a center of curvature CCR that is located on the same side ofthe road 88 as the center of curvature CC of the wind turbine blade 20.The curvature of the wind turbine blade 20 also limits the amount ofintrusion into the other lane 86 on the road 88 during the turningmovement. As a result, the transportation device 30 a and wind turbineblade 20 can advantageously traverse much sharper curves and turns thanconventional transportation devices. Following the turn, thetransportation device 30 a rotates the wind turbine blade 20 back to thefirst orientation to contain the transportation device 30 a within onelane 86 as previously described. This improvement allows the windturbine blade 20 to be transported along more direct routes than whatmay be required otherwise, thereby enabling faster and more efficienttransport of the wind turbine blade 20 to the assembly site or quayside.It will be appreciated that the wind turbine blade 20 can rotate to thesecond orientation in either direction such that turns or curves in bothdirections may be traversed more easily. Furthermore, it will beunderstood that the wind turbine blade 20 may be rotated to the secondorientation before traversing a turn when the road 88 provides enoughoverall width for the second trailer 82 to translate outwardly as shownin FIG. 5C, or may be rotated to the second orientation only during theturning motion when the road is narrower to avoid pushing the secondtrailer 82 off the side of the road 88.

Additionally, the rotation of the wind turbine blade 20 from the firstorientation to the second orientation also has additional benefitsduring transport. For example, the curved nature of the wind turbineblade 20 and the high flapwise width FW may make the combined tractor 32a and blade 20 too tall to pass under certain bridges on the road 88.However, turning the wind turbine blade 20 to the second orientationreduces the overall height as a result of the edgewise width EW beingsmaller than the flapwise width FW, which enables the transportationdevice 30 a to pass under those bridges. This benefit is shown by thephantom line bridge overpass 100 shown in the rear views of FIGS. 6A and6B. Thus, the transportation device 30 a of the current inventionenables transport of large curved wind turbine blades 20 along a higherpercentage of the existing network of roads and provides multiplebenefits.

With reference to FIGS. 7A-8C, a second embodiment of a transportationdevice 30 b according to the invention is shown. As with the previouslydescribed embodiment, the transportation device 30 b and all previouslydescribed components are shown with the same reference numbers whereappropriate, with the addition of an “b” on the end of the referencenumber to indicate this particular embodiment. The transportation device30 b of this embodiment includes a unitary tractor 32 b without anytrailers. Thus, the tractor 32 b includes a first support bearing 34 band a second support bearing 36 b as previously described, which receivethe wind turbine blade 20 therethrough. More specifically, the firstsupport bearing 34 b is located near the cab 48 and receives the windturbine blade 20 proximate the root end 26, while the second supportbearing 36 b is located at a rear end of the tractor 32 b and receivesthe wind turbine blade 20 proximate a central portion. In this regard,the wind turbine blade 20 is fully supported at two locations along itslongitudinal length. It will be understood that more than two supportbearings may be provided on the tractor 32 b in other embodimentsconsistent with the scope of the invention, depending on, for example,the length of the wind turbine blade 20 and possibly other factors.

Returning to FIGS. 7A-7C, the wind turbine blade 20 is loaded onto thetransportation device 30 b in a first orientation in which the curvedcentral longitudinal axis 24 of the blade 20 is located in a generallyvertical plane substantially located (or only slightly offset from)along a longitudinal centerline LC of the tractor 32 b. As shown in theside view of FIG. 7A, the curvature of the central longitudinal axis 24also generally defines a center of curvature CC located within thatvertical plane roughly centered on the tractor 32 b. The curvature ofthe central longitudinal axis 24 in this embodiment is once again alongthe flapwise direction (i.e., between the pressure side and the suctionside of the blade 20), which causes the wind turbine blade to define alarger flapwise width FW than an edgewise width EW. Accordingly, thewind turbine blade 20 is loaded and normally kept in this firstorientation so that the transportation device 30 b and the wind turbineblade 20 in combination fit within the boundaries of a lane 86 on a road88 as shown in FIG. 7C.

As shown in the first orientation of FIGS. 7A and 7B, the first supportbearing 34 b is pivoted in the X-axis slightly towards the secondsupport bearing 36 b so that the corresponding supports 68 b follow theprofile of the wind turbine blade 20 near the root end 26 and thecentral portion. Also in this first orientation, the bearing drivedevice 66 b of the first support bearing 34 b extends the correspondingsupport arms 62 b higher than the support arms 62 b of the secondsupport bearing 36 b at the center of the wind turbine blade 20. Thecounterweight 56 b is also centrally located on the tractor 32 b becausethe mass of the wind turbine blade 20 is not located substantiallyoff-center from the longitudinal centerline LC. Accordingly, each of thesupport bearings 34 b, 36 b reliably supports the corresponding sectionof the wind turbine blade 20 during normal transport with thetransportation device 30 b.

When the transportation device 30 b approaches a turn or curve in theroad 88 (as sensed/determined by one or more of the various sensingdevices 44 described above), the controller 42 actuates rotation of thewind turbine blade 20 generally about the central longitudinal axis 24to a second orientation with the drive mechanism 38 b, or alternatively,with the bearing drive device 66 b, as shown in FIGS. 8A-8C. Aspreviously described, the drive mechanism 38 b may directly engage androtate the wind turbine blade 20 such as at the root end 26, or thedrive mechanism 38 b may rotate the supports 68 b of the correspondingsupport bearings 34 b, 36 b to rotate the wind turbine blade 20. Ineither case, the wind turbine blade 20 rotates generally about itscentral longitudinal axis 24.

In addition to the rotation of the wind turbine blade 20 along thecentral longitudinal axis 24, the controller 42 may also actuateadditional movements of the first support bearing 34 b and thecounterweight 56 b. More particularly, the bearing drive device 66 b ofthe first support bearing 34 b translates the corresponding support arms62 b downwardly along the Y-axis while the support arms 62 b of thesecond support bearing 36 b remain fixed in position. This translationalmovement is shown by arrow 110 in FIG. 8A. Additionally, the firstsupport bearing 34 b freely rotates about both the transverse X-axis (asshown by arrow 112 in FIG. 8A) and the vertical Y-axis (as shown byarrows 114 in FIG. 8B) to pivot away from the second support bearing 36b to accommodate the rotation of the wind turbine blade 20. Although thesecond support bearing 36 b is shown with no rotational movements inthese figures, it will be understood that the second support bearing 36b may rotate about these X and Y axes in some embodiments depending onthe particular shape and profile of the wind turbine blade 20. Thecollective effect of each of these rotational and translationalmovements is that the wind turbine blade 20 rotates to the secondorientation in which the curved central longitudinal axis 24 is disposedin a generally horizontal plane as shown. To this end, the curvedcentral longitudinal axis 24 is moved to bend around the turn to beperformed.

At the same time as these rotational and translational movements of thefirst support bearing 34 b, the controller 42 may move the counterweight56 b with respect to the longitudinal centerline LC to the opposite side(35 b) of the tractor 32 b as the central portion of the wind turbineblade 20 to equalize force-moments applied to the tractor 32 b. In otherwords, the counterweight 56 b moves to the same side 35 b of the tractor32 b as the center of curvature CC of the central longitudinal axis 24of the blade 20. The likelihood of the transportation device 30 btipping over while traversing the turn is reduced by this movement ofthe counterweight 56 b.

The benefits of rotating the wind turbine blade 20 to the secondorientation are most clearly shown in FIG. 8C, which illustrates thetransportation device 30 b of this embodiment during the turn around thecurve in the road 88. In contrast to the turn illustrated on the outerside of the road in FIG. 2A, the movements of the wind turbine blade 20and the transportation device 30 b to the second orientation enable thewind turbine blade 20 to bend around the curve rather than swing the tipend 28 of the blade 20 across a boundary 98 of the road 88. Morespecifically, the curve generally defines a center of curvature CCR thatis located on the same side of the road 88 as the center of curvature CCof the wind turbine blade 20. The curvature of the wind turbine blade 20also limits the amount of intrusion into the other lane 86 on the road88 during the turning movement. As a result, the transportation device30 b and wind turbine blade 20 can advantageously traverse much sharpercurves and turns than conventional transportation devices. Following theturn, the transportation device 30 b rotates the wind turbine blade 20back to the first orientation to contain the transportation device 30 bwithin one lane 86 as previously described. This improvement allows thewind turbine blade 20 to be transported along more direct routes thanwhat may be required otherwise, thereby enabling faster and moreefficient transport of the wind turbine blade 20 to the assembly site orquayside.

It is clear to the skilled person that all the Figs. show a left handturn, but that a right hand turn might as well be performed. In case achord width is very large, i.e. large a width transverse to the line 24,FIGS. 8A, 7B, 5A and 4B, it may be an option to elevate the blade 20 bythe support arms 62 b and bearing drive devices 66 b, before rotatingthe blade into the have an orientation suitable for and corresponding tothe direction of the road turn.

While the invention has been illustrated by a description of variousembodiments, and while these embodiments have been described inconsiderable detail, it is not the intention of the applicant torestrict or in any way limit the scope of the appended claims to suchdetail. Additional advantages and modifications will readily appear tothose skilled in the art. The invention in its broader aspects istherefore not limited to the specific details, representative methods,and illustrative examples shown and described. Accordingly, departuresmay be made from such details without departing from the spirit or scopeof the general inventive concept.

What is claimed is:
 1. A transportation device for transporting a windturbine blade defining a curved central longitudinal axis, thetransportation device comprising: a tractor; a first support bearingcoupled to the tractor and configured to receive the wind turbine bladetherethrough; a second support bearing configured to receive the windturbine blade therethrough; a wind turbine blade having a curved centrallongitudinal axis and being supported by the first and second supportbearing, and a drive mechanism operable to rotate the wind turbine bladewithin the first and second support bearings between a first orientationin which the curved central longitudinal axis is located in a generallyvertical plane and a second orientation in which the curved centrallongitudinal axis is located in a generally horizontal plane, and acontroller arranged to actuate the drive mechanism and thereby actuaterotational movement of the wind turbine blade between the first and thesecond orientation as well as between the second and the firstorientation, wherein when the tractor is preparing to turn in a turningdirection, the drive mechanism rotates the wind turbine blade to thesecond orientation before or during turning such that the curved centrallongitudinal axis bends in the turning direction.
 2. The transportationdevice according to claim 1, further comprising: a sensing deviceconfigured to determine when the tractor is preparing to drive around acurve; and a controller operatively coupled to the sensing device andthe drive mechanism, the controller operable to actuate the drivemechanism to rotate the wind turbine blade before the tractor drivesaround the curve.
 3. The transportation device according to claim 2,wherein the sensing device includes a user interface for receivingcommands from a driver of the tractor, and the controller receives asignal from the user interface when the driver determines that the windturbine blade requires rotation.
 4. The transportation device accordingto claim 2, wherein the sensing device includes a turning sensor locatedon a steering wheel of the tractor, and the controller automaticallyactuates the drive mechanism to rotate the wind turbine blade wheneverthe turning sensor sends a signal indicating that the steering wheel isturning beyond a predetermined threshold.
 5. The transportation deviceaccording to claim 2, wherein the sensing device includes a globalpositioning system that detects when the tractor is approaching a curveand the controller automatically actuates the drive mechanism to rotatethe wind turbine whenever the global positioning system has detectedthat the tractor is approaching a curve.
 6. The transportation deviceaccording to claim 2, wherein the tractor includes first and secondsides, the curved central longitudinal axis is curved about a center ofcurvature, and the transportation device further comprises: acounterweight moveably mounted on the tractor, wherein the controller isconfigured to actuate movement of the counterweight towards the sameside of the tractor as the center of curvature during rotation of thewind turbine blade towards the second orientation.
 7. The transportationdevice according to claim 1, wherein the second support bearing isfixedly coupled to the tractor, and the transportation device furthercomprises: a first bearing drive device operatively coupled to the firstsupport bearing and configured to translate the first support bearing ina vertical direction relative to the second support bearing duringrotation of the wind turbine blade between the first and secondorientations.
 8. The transportation device according to claim 7, whereinthe first support bearing further includes a frame pivotally coupled tothe tractor, the frame enabling free rotation of the first supportbearing about a horizontal axis transverse to the central longitudinalaxis and rotation about a vertical axis during rotation of the windturbine blade between the first and second orientations.
 9. Thetransportation device according to claim 8, wherein the first supportbearing further comprises: a support disposed within the frame andincluding an aperture sized to closely receive the wind turbine bladetherethrough; and an annular bearing positioned between the frame andthe support and configured to enable free rotation of the support andthe wind turbine blade along the central longitudinal axis.
 10. Thetransportation device according to claim 1, further comprising: a firsttrailer coupled to the tractor by the wind turbine blade, the secondsupport bearing being coupled to the first trailer; and a first bearingdrive device operatively coupled to the first support bearing andconfigured to translate the first support bearing in a verticaldirection during rotation of the wind turbine blade between the firstand second orientations.
 11. The transportation device according toclaim 10, further comprising: a second bearing drive device operativelycoupled to the second support bearing and configured to translate thesecond support bearing in a vertical direction during rotation of thewind turbine blade between the first and second orientations.
 12. Thetransportation device according to claim 11, wherein each of the firstand second support bearings further includes a frame pivotally coupledto the tractor or the first trailer, the frames enabling free rotationof the first and second support bearings towards or away from each otherabout corresponding horizontal axes transverse to the centrallongitudinal axis during rotation of the wind turbine blade between thefirst and second orientations.
 13. The transportation device accordingto claim 12, wherein each of the first and second support bearingsfurther comprises: a support disposed within the frame and including anaperture sized to closely receive the wind turbine blade therethrough;and an annular bearing positioned between the frame and the support andconfigured to enable free rotation of the support and the wind turbineblade along the central longitudinal axis.
 14. The transportation deviceaccording to claim 11, further comprising: a second trailer locatedbetween the tractor and the first trailer; a third support bearingcoupled to the second trailer and configured to receive the wind turbineblade therethrough; and a third bearing drive device operatively coupledto the third support bearing and configured to optionally translate thethird support bearing in a vertical direction opposite the translatingmovement of the first and second support bearings during rotation of thewind turbine blade between the first and second orientations.
 15. Thetransportation device according to claim 1, wherein the drive mechanismis independent from the first and second support bearings.
 16. Thetransportation device according to claim 1, wherein the drive mechanismis operatively associated with at least one of the first and secondsupport bearings.